Return a boolean for value.
Return value when value is a python bool type.
Return True for strings ‘true’, ‘yes’, ‘t’, ‘y’, and ‘1’.
Return False in all other cases, including when value is an empty string or
None

This function applies general validation rules for names of packages,
groups, users, etc.

Most schemas also have their own custom name validator function to apply
custom validation rules after this function, for example a
package_name_validator() to check that no package with the given name
already exists.